package com.youjiang.meeting.utils.weixin;

import java.security.MessageDigest;
import java.util.Arrays;

public class CheckUtil {
	
	public static boolean checkSignature(String signature,String timestamp,String nonce){
//		String[] arr=new String[]{WeixinUtil.Token,timestamp,nonce};
		String[] arr=new String[]{"towngasTokens",timestamp,nonce};
		Arrays.sort(arr);
		StringBuffer buf=new StringBuffer();
		for(int i=0;i<arr.length;i++){
			buf.append(arr[i]);
		}
		String signature2=getSha1(buf.toString());
		
		return signature.equals(signature2);
	}
	
	public static String getSha1(String str){
		if (null == str || 0 == str.length()){
		return null;
		}
		char[] hexDigits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 
		'a', 'b', 'c', 'd', 'e', 'f'};
		try {
		MessageDigest mdTemp = MessageDigest.getInstance("SHA1");
		mdTemp.update(str.getBytes("UTF-8"));

		byte[] md = mdTemp.digest();
		int j = md.length;
		char[] buf = new char[j * 2];
		int k = 0;
		for (int i = 0; i < j; i++) {
		byte byte0 = md[i];
		buf[k++] = hexDigits[byte0 >>> 4 & 0xf];
		buf[k++] = hexDigits[byte0 & 0xf];
		}
		return new String(buf);
		} catch (Exception e) {
		return null;
		}
		}
}
